The present invention relates to intravascular devices and, in particular, to an intravascular device such as an improved introducer sheath used for positioning a catheter, imager, or other device in the vascular system of a patient or an intravascular device such as a balloon catheter with a new design and construction.
Various therapies have been developed for treating vascular disease or other conditions that occlude or reduce the lumen size of portions of the vascular system. Such therapeutic techniques include angioplasty, atherectomy, laser irradiation, and so on. Diagnostic techniques have been developed to measure or image the extent of an occlusion of a vessel (e.g., stenosis). Such diagnostic techniques include ultrasonic imaging, Doppler measurements, and so on. These therapies and diagnostic techniques have achieved acceptance because of their effectiveness as well as the fact that they can be performed through a minor surgical procedure that is relatively non-disruptive to the patient.
Therapeutic and diagnostic procedures, such as those described above, rely on the positioning of a device into the vascular system of a patient via an incision at a location remote from the site of the stenosis, such as the femoral artery. Because each of the aforementioned therapies and diagnostic procedures relies upon positioning a device in the afflicted area, an important defining factor limiting the effective deployment of any of these devices is how small the device can be made. It is often in vessels of small inner diameters or tortuous passage ways that stenosis occurs. Thus, it is often preferable to make such therapeutic and diagnostic devices as small as possible to fit into remote coronary sites or other vessel locations where the vessel lumen inner diameters are very small.
Some therapeutic and diagnostic devices include their own guidewires located at the distal ends thereof to facilitate positioning in remote vessel locations. Other devices use an over-the-wire approach in which a central lumen of the device can accommodate a guidewire that is movable in relation to the device to facilitate positioning the device in a remote vessel location. Both of these approaches are very useful and are widely used. However, when such therapeutic or diagnostic devices are adapted with a positioning feature, such as a guidewire tip or a central lumen, the addition of such a positioning feature can increase the size of the device somewhat, thereby establishing a limitation on the size of a vessel into which it can be deployed that is larger than if such an additional feature were omitted.
Introducer sheaths have been employed to facilitate positioning therapeutic and diagnostic devices in remote regions of the vascular system. An introducer sheath can be a catheter-like device. In a typical prior introducer sheath, the distal end of the introducer sheath is positioned inside of the guide catheter close to the desired site and the therapeutic or diagnostic device is inserted through the lumen of the introducer sheath out the distal end thereof into the vessel location. The introducer sheath also provides the advantage that it can support the therapeutic or diagnostic device over all but the most distal end thereof. Introducer sheaths may be positioned by a guidewire that is first inserted through the lumen of the introducer sheath and then withdrawn to allow placement of the therapeutic or diagnostic device to be installed into the lumen.
A disadvantage of using such a prior introducer sheath is that if it is necessary to reposition the therapeutic or diagnostic device, the introducer sheath may also have to be repositioned. Repositioning of the introducer sheath may require withdrawing the therapeutic or diagnostic device, installing a guidewire into the lumen of the introducer sheath, positioning the guidewire past the distal end of the introducer sheath to the desired location, repositioning the introducer sheath, withdrawing the guidewire, and reintroducing the therapeutic or diagnostic device. This can be a time consuming and tedious process.
Accordingly, it is an object of the present invention to provide an introducer sheath that facilitates use and placement of devices in a vessel of a patient.
It is another object of the present invention to provide an introducer sheath that permits use in remote, distal portions of patient's vasculature.